Three gain stages vs 4 or more for high gain

[bubbastain]

Are Marshall type modded amps with two CF slots common?

 

[fusedbrain]

@fusedbrain

Do you have an opinion on the number of stages/configuration combined with a different power tube section?

I would be inclined to say that an EL34 power section would be the least tolerant of an over-cooked pre amp design.
I perceive EL34's to have the most mid range, and most compression of the bigger bottle power tubes. EL34's can also get that " harmonic swirl " thing going on that adds to the "plexi magic" in the early Marshalls.
To me, those attributes are not going to mate as well with a multi gain stage, over the top pre amp designs as say a quad of KT88's or 6550's.
I've always perceived 6550's and KT88's as stiffer and more focused tubes, and I like to use them with certain high gain amp designs.
I run 6550's in my home brew Cali / CCV diode clipping Marshall because it seems like they match up better with the 2N5400's and all the saturation the diodes bring to the table.
The Fortin Cali modded Marshall I used to own sounded best to me with 6550's
The Peters FSM ( one of his highest gain designs ) sounds best to me with KT88's
My VH-4 sounds great with KT77's, and sounded fabulous with 6550's as well.
A Rev G Triple Rec sounds WAY better to me with 6L6's vs EL34's.
This stuff is all subjective though, and we all hear things differently.
And we haven't even started talking about "feel " yet ....

 

[glip22]

Lots of variables. I recently added a three way NFB switch to my amp. As posted power amp makes a huge difference. The switch completely changes the character of the amp in a big way. The amp is four stages or three in the low input so you can have the option. Options are cool.

Three stages definitely cleans up better but it all depends on other factors such as how the preamp tubes are biased. Dynamics is another factor. It's not necessarily how many stages there are that affects dynamics, and clarity but it definitely plays a part.
So many factors I don't pretend to fully understand.

 

[petejt]

So here is the Recto preamp. Don't know how the power section and tone stack fit in but it appears this is a pretty standard set up for all Rectos. I know the tone controls affect the gain structure significantly but don't know how it matches up with the Marks (or other amps).

The Recto preamps are the Marshall-type tone stack (even though the tone is completely different to Marshall), i.e. "post-gain" EQ. From what I know so far it amplifies the signal through the gain stages, then runs the signal through the treble, bass, and midrange sections.

The Mark series are a very different beast. They use pre-gain EQ, where the tone controls come before (at least most of) the gain stages. This is why running the treble really high allows it to get more strongly distorted, and turning the bass too high makes it muddy.

By the looks of it, the MarkIV has one gain stage for the rhythm channels (V2a), after the input stage (V1a) and the "tone recovery" stage (V2b) which I speculate don't amplify the signal.

When the Lead channel is selected, it switches the signal to V3a (Lead Gain?) and V4a (Lead Drive?), then sends it to V2a, effectively sending it through five gain stages. To me though this contradicts what I said about V1 not amplifying the signal. Also that confuses me because that would imply that the Rhythm 1 & Rhythm 2 gain controls affect the Lead channel... What am I doing here?
If you know this stuff better, please clarify this, thanks.

 

[skullfxr]

@fusedbrain

Do you have an opinion on the number of stages/configuration combined with a different power tube section?

I would be inclined to say that an EL34 power section would be the least tolerant of an over-cooked pre amp design.
I perceive EL34's to have the most mid range, and most compression of the bigger bottle power tubes. EL34's can also get that " harmonic swirl " thing going on that adds to the "plexi magic" in the early Marshalls.
To me, those attributes are not going to mate as well with a multi gain stage, over the top pre amp designs as say a quad of KT88's or 6550's.
I've always perceived 6550's and KT88's as stiffer and more focused tubes, and I like to use them with certain high gain amp designs.
I run 6550's in my home brew Cali / CCV diode clipping Marshall because it seems like they match up better with the 2N5400's and all the saturation the diodes bring to the table.
The Fortin Cali modded Marshall I used to own sounded best to me with 6550's
The Peters FSM ( one of his highest gain designs ) sounds best to me with KT88's
My VH-4 sounds great with KT77's, and sounded fabulous with 6550's as well.
A Rev G Triple Rec sounds WAY better to me with 6L6's vs EL34's.
This stuff is all subjective though, and we all hear things differently.
And we haven't even started talking about "feel " yet ....

Thank you for the thorough response. Your knowledge far exceed mine in that regard. As far as my amp tweaking, I am a basic blackface fender guy, never really tore into anything super high fain or complex in that matter.

Your impressions are similar to what I had in my head regarding power tube selection. I have (believe it or not) never jumped into the Jose rabbit hole, but real quick, do any of my amps have the diode clippers? I am not really sure as dumb as that may sound.

Again some things I tear into and some things I don't. I don't feel knowledgeable enough to understand the design and/or tweak a really high gain amp, because I am not sure I have the knowledge to do it well enough to keep it quiet and in check and especially not a super complex design.

 

[JMP2203]

mark 2c+ and mark iv lead channel are 5 gain stages and recto are 4 + CF(same as SLO100)

and yes Mark amps use tone stack before gain stages and recto after

to add some more info on Hi Gain amps:

JVM - 4 Gain stages + CF
ENGL - 4 Gain stages without CF
5153 Blue channel - 4 gain stages + CF
5152 Crunch Channel - 3 Gain stages without CF

 

[glpg80]

I’m definitely a boosted 3 stage guy with a cathode follower over a 4 gain stage design plate fed tone stack or cathode follower.

I like the clarity on the top end with the boosted 3 gain stage and like how responsive it is over a 4 gain stage design.

Anyone who says a Peavey era 5150 is compressed isn’t playing it loud enough - they are voiced to be ran way higher than what most clubs allow but sound best there. It’s a well balanced design not made to be a bedroom amp.

I’ve also learned I don’t like diode clipping in an amplifier. I’d prefer saturation from the least number of stages possible by a hot pickup or boost, or both.

I had a friend who loved his 3 stage Marshall and modded it to have a 4th stage, then never played it again. Totally choked the amp and it never cut live again. He had it modded back to stock and went synergy after. Yes a boost pedal is a pain to lug around but if it nails the sonic character you’re looking for then it isn’t all that bad.

My 74 is a 3 stage cathode follower fed design and with a boost has more than enough gain on tap at any volume for my needs. I don’t get the infatuation with 5150 III levels of gain though - to me that is way over the top and more than anyone ever needs.

 

[Kapo_Polenton]

I’m definitely a boosted 3 stage guy with a cathode follower over a 4 gain stage design plate fed tone stack or cathode follower.

I like the clarity on the top end with the boosted 3 gain stage and like how responsive it is over a 4 gain stage design.

Anyone who says a Peavey era 5150 is compressed isn’t playing it loud enough - they are voiced to be ran way higher than what most clubs allow but sound best there. It’s a well balanced design not made to be a bedroom amp.

I’ve also learned I don’t like diode clipping in an amplifier. I’d prefer saturation from the least number of stages possible by a hot pickup or boost, or both.

I had a friend who loved his 3 stage Marshall and modded it to have a 4th stage, then never played it again. Totally choked the amp and it never cut live again. He had it modded back to stock and went synergy after. Yes a boost pedal is a pain to lug around but if it nails the sonic character you’re looking for then it isn’t all that bad.

My 74 is a 3 stage cathode follower fed design and with a boost has more than enough gain on tap at any volume for my needs. I don’t get the infatuation with 5150 III levels of gain though - to me that is way over the top and more than anyone ever needs.

100% agree as a boost it guy myself. Besides, most of the time people have a pedal board with effects on it anyway so what is the big deal with a 5 inch boost pedal? Also for rythm, less gain cuts more over saturation...the secret sauce to AC DC's tone, less gain! I also second the hotter pickups. They really shine on an amp with less gain on tap.

 

[glpg80]

Yep agreed. I dial my Marshall in for a good rhythm tone and use the boost to take it over the top for solos. I’ll take a well balanced 3 stage marshall in the right hands over a 6 channel Randall 667 anyday.